1. Field of the Invention
The present invention relates generally to personal audio devices such as headphones that include adaptive noise cancellation (ANC), and, more specifically, to power management in an ANC system.
2. Background of the Invention
Wireless telephones, such as mobile/cellular telephones, cordless telephones, and other consumer audio devices, such as MP3 players, are in widespread use. Performance of such devices with respect to intelligibility can be improved by providing adaptive noise canceling (ANC) using a reference microphone to measure ambient acoustic events and then using signal processing to insert an anti-noise signal into the output of the device to cancel the ambient acoustic events.
Since personal devices such as those described above are generally battery-powered, power management of features within the device are needed in order to extend battery life. Further, reduction of power consumption of electronic devices is desirable in general. Therefore, it would be desirable to provide a personal audio device, including a wireless telephone, which provides noise cancellation in which the noise cancellation features are power-managed.